Some of my favorite quotes so far:
Of Mort
It was also acutely embarrassing to Mort’s family that the youngest son was not at all serious and had about the same talent for horticulture that you would find in a dead starfish. It wasn’t that he was unhelpful, but he had the kind of vague, cheerful helpfulness that serious men soon learn to dread.
Of Ankh-Morpork
This part of Ankh-Morpork was known as The Shades, an inner-city area sorely in need either of governmental help or, for preference, a flamethrower. It couldn’t be called squalid because that would be stretching the word to breaking point. It was beyond squalor and out the other side, where by a sort of Einsteinian reversal it achieved a magnificent horribleness that it wore like an architectural award.
Of the River Ankh
And so Mort came at last to the river Ankh, greatest of rivers. Even before it entered the city, it was slow and heavy with the silt of the plains, and by the time it got to The Shades even an agnostic could have walked across it. It was hard to drown in the Ankh, but easy to suffocate.